Simplify the following expression: $k = \dfrac{30yz}{10xz} + \dfrac{50z^2 + 10z}{10xz}$ You can assume $x,y,z \neq 0$.
Explanation: Since the expressions have the same denominator we simply combine the numerators: $k = \dfrac{30yz + 50z^2 + 10z}{10xz}$ The numerator and denominator have a common factor of $10z$, so we can simplify $k = \dfrac{3y + 5z + 1}{x}$